Rixensart is a Walloon municipality located in the Belgian province of Walloon Brabant. On January 1, 2006, Rixensart had a total population of 21,355. The total area is 17.54 km² which gives a population density of 1,217 inhabitants per km².
The municipality consists of the following former municipalities, now sub-municipalities: Rixensart proper, Rosières (Rozieren), and Genval. Genval-les-Bains is a local beauty spot, a 100-year-old lake with a fountain, and framed by trees, houses and restaurants. Rixensart is home to the beautiful private-owned Château de Rixensart.